Nebulizing Poractant Alfa Versus Conventional Instillation: Ultrastructural Appearance and Preservation of Surface Activity

BackgroundNebulized surfactant therapy has been proposed as an alternative method of surfactant administration. The use of a perforated vibrating membrane nebulizer provides a variety of advantages over conventional nebulizers. We investigated the molecular structure and integrity of poractant alfa pre- and post-nebulization. MethodCurosurf (R) was nebulized using an Investigational eFlow (R) Nebulizer System. Non-nebulized surfactant (NN), recollected surfactant droplets from nebulization through an endotracheal tube (NT) and nebulization of surfactant directly onto a surface (ND) were investigated by transmission electron microscopy. Biophysical characteristics were assessed by the Langmuir-Wilhelmy balance and the Captive Bubble Surfactometer. ResultsVolume densities of lamellar body-like forms (LBL) and multi-lamellar forms (ML) were high for NN and NT samples (38.8% vs. 47.7% for LBL and 58.2% vs. 47.8% for ML). In the ND sample, we found virtually no LBL's, ML's (72.6%) as well as uni-lamellar forms (16.4%) and a new structure, the garland-like forms (9.4%). Surface tension for NN and NT was 23.330.29 and 25.77 +/- 1.12mN/m, respectively. Dynamic compression-expansion cycling minimum surface tensions were between 0.91 and 1.77mN/m. ConclusionThe similarity of surfactant characteristics of nebulized surfactant via a tube and the non-nebulized surfactant suggests that vibrating membrane nebulizers are suitable for surfactant nebulization. Alterations in surfactant morphology and characteristics after nebulization were transient. A new structural subtype of surfactant was identified. Pediatr Pulmonol. 2014; 49:348-356. (c) 2013 Wiley Periodicals, Inc.